Biosorption of methylene blue from aqueous solution by poly(amic acid)-modified chitosan



The purpose of the research was to investigate effects of temperature, initial pH, initial concentration, and contact time on the biosorption of methylene blue (MB) by modified chitosan using a batch technique. The modified chitosan was prepared by grafting poly (amic acid), which was obtained via reaction of pyromellitic dianhydride (PMDA) and l-arginine, onto the surface of cross-linked chitosan. The MB sorption process was evaluated at 25, 35, and 45°C. Results showed that the modified chitosan had a good capacity for biosorption of MB. The kinetic behavior was described by pseudo-second-order model. The experimental isotherms obtained were fitted better with Langmuir model than Freundlich model. According to the Langmuir equation, the maximum uptake capacity (qm) for MB was 392.16 mg g−1. Thermodynamic parameters math formulaand math formulawere calculated using the Van't Hoff equation, and results showed that MB sorption by modified chitosan was an exothermic and spontaneous process. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1180–1186, 2014